JP2969899B2 - Resin composition for sealing - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a resin composition used as a sealing body for sealing semiconductors, resistors, capacitors, and other electronic components.

(Prior art) With the recent development of electronic circuit technology, semiconductors, resistors,
Applications for capacitors and other electronic components are constantly expanding. These electronic components are often sealed and used for the purpose of integration, mechanical protection, prevention of characteristic fluctuation caused by an external atmosphere, and the like. As the sealing material, a synthetic resin is generally used from the viewpoints of ease of sealing molding, electrical insulation and the like. In addition, measures such as providing a heat sink or a radiator plate, or performing sealing molding in such a form have been taken for sealing of a material such as a resistor that generates heat during operation of a circuit, such as a resistor. . On the other hand, a method of sintering and sealing using alumina without using a synthetic resin as a sealing material has been proposed.

(Problems to be Solved by the Invention) In order to seal electronic components that generate heat, the above-described countermeasures have been taken, but these methods have the following problems. That is, the method of providing the heat sink and the heat radiating plate has problems in that the structure of the sealing molding becomes complicated, the structure becomes large, which prevents the circuit from being reduced in size and weight, and the production cost is greatly disadvantageous. Further, the method of sintering and sealing using alumina has a problem that productivity is low and cost disadvantage is large.

In order to cope with these problems, an attempt has been made to use a resin compound containing alumina powder and having improved thermal conductivity (Japanese Patent Application Laid-Open No. 62-240313). In this trial, the heat dissipation of the mold resin was estimated from the thermal resistance value of the mold package, and the effect was only confirmed with the operating life time under high temperature of the video RAM.
For example, the durability as a sealing material of a high heating element such as a resistor is still insufficient.

The present inventors made a compound using a polyphenylene sulfide resin (hereinafter, referred to as PPS) as a base material resin, and made a compound using alumina powder as a filler, sealed a resistor with this compound, and conducted an electrical test. As a result, it was recognized that cracks occurred in the sealed body.

As described above, the resin compound containing the alumina powder still has many problems as a sealing material for an electronic component that generates heat, particularly for a high-heating element, and can be manufactured at a low cost with a simple structure, and At present, there is a need for a sealing material that can withstand long-term use without causing melting or cracking of the sealing body even during operation of the circuit.

An object of the present invention is to provide a resin composition having good thermal conductivity and excellent mechanical strength without cracks, as a material having good properties for encapsulation of a high heating element. It is.

(Means for Solving the Problems) In order to address the above-mentioned problems, the present inventors have conducted various studies, and as a result, a resin composition containing PPS and fibrous and / or whisker-like aluminum borate, As a sealing material for an electronic component that generates heat, particularly a high heat generating element such as a resistor, the present inventors have found that this is an effective means for solving these problems, and have completed the present invention.

That is, the present invention provides a sealing resin composition comprising a polyphenylene sulfide resin and fibrous and / or whisker-like aluminum borate.

PPS used in the present invention is preferably one having a high melt flow index in order to more easily perform sealing molding of an electronic component, but is not particularly limited. Preferred melt flow index of PPS (temperature 300 ° C, load 2
160g) is 100-700g / 10 minutes, more preferably 200-500g / 10
Minutes.

The aluminum borate used in the present invention has a fibrous shape, a whisker shape, or the like as its shape, and a preferred example is Arboresque G (manufactured by Shikoku Chemical Industry Co., Ltd.). Arbolex G is 9AI ₂ O ₃・ 2B ₂ O ₃
Whiskers of aluminum borate represented by
It is a white needle-like crystal having a length of 10 to 30 μm and a diameter of 0.5 to 1.0 μm.

The compounding amount of the composition of the present invention is preferably 20 to 60% by weight, particularly 35 to 50% by weight, and 40 to 80% by weight, particularly preferably 50 to 65% by weight of aluminum borate. This composition ratio was obtained as a result of conducting studies from all angles, such as compounding properties, encapsulation moldability, thermal conductivity of the encapsulant, and durability test for energization of the encapsulation of the resistor.

In the invention of the present application, increasing the content of aluminum borate impairs compoundability and sealing moldability, and conversely, by lowering the thermal conductivity of the sealing body is reduced, as a result, during energization A tendency was observed that the amount of heat stored in the sealed body was increased and melting and destruction were likely to occur. In addition, aluminum borate was included in the resin composition and also acted as a reinforcing material, and the result was that durability against crack breakage was sufficient.

Although the composition ratio of PPS and aluminum borate is closely related to the compound and the characteristics of the sealed body as described above, the composition ratio applied to the present invention is not particularly limited, and the The composition ratio can be arbitrarily selected beyond the range of the composition ratio described above according to the characteristics of the electronic component.

(Examples) Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

In addition, each test method in an Example is as follows.

Compoundability The compoundability was determined by visually observing the composition discharged from the twin-screw extruder and by the load applied to the twin-screw extruder.

Melt Viscosity The melt viscosity was measured at 300 ° C. with a load of 50 kg using a “Flow Tester CFT-500” manufactured by Shimadzu Corporation. This melting temperature is one of the criteria for judging the difficulty of the sealing molding.

Thermal conductivity The thermal conductivity was measured by measuring the composition to 100 × 100 × 3 mm
Were injection molded into a plate shape, and five of them were stacked and measured. At this time, silicon grease was minimally filled to fill the voids of the stacked plates. As a measuring instrument, "Rapid thermal conductivity meter Kem-therm QTM-D3" manufactured by Kyoto Electronics Industry Co., Ltd. was used.

Electricity endurance test (1) Applying a predetermined DC voltage to the electric endurance test resistor against melting and destruction, and energize. After the energization was started, the time required for the sealed body to melt and break was measured and defined as the endurance time. For the DC voltage applied to the resistor, the load was changed in units of 1 W, and the endurance time was determined for each load.

(2) Apply a DC voltage to the resistance test for resistance to cracking to 4 W or 5 W.
After 80 hours of continuous energization, the voltage was released, and the resistors were left at room temperature for 24 hours, and then energized again with the same load.
After continuous application of electricity for 72 hours, the voltage was released. After standing for 24 hours, the battery was further supplied with the same load for 72 hours, and then the voltage was released. At this time, the time when cracks occurred in the sealed body was used as an index of durability against crack breakage.

Examples 1 to 3 and Comparative Examples 1 to 3 Each compound was prepared according to the composition ratio shown in Table 1. At this time, the aluminum borate has a diameter of 0.5 to 1 μm.
m, whiskers having a length of 10 to 30 μm were used. A powder having an average particle diameter of alumina of 2.2 μm was used, and a glass fiber having a fiber diameter of 12 μm and a length of 6 mm was used. The compounding was performed by a three-row twin screw extruder. According to this method, compounding was impossible in Comparative Example 2.
Using the other obtained compounds, a resistor was sealed and molded by an injection molding machine. FIGS. 1 (perspective view) and 2 (cross-sectional view) show the shape of the sealed resistor. The resistor used has a resistance value of 10Ω.

As is clear from Table 1, the durability against melt fracture was 6 W (Example 1) in the composition containing 50% by weight of aluminum borate whiskers, and 8 W (Examples 2 and 3) in the composition containing 60 to 65% by weight. 4) glass fiber reinforced PPS compound that does not contain aluminum borate whiskers
It can be seen that the durability is improved as compared with W (Comparative Example 1).

In addition, the effect of aluminum borate whiskers is remarkable with respect to the durability against crack breakage.
Load of about 65% by weight (Examples 1, 2, 3)
No cracks were observed in both W and 5W.

The effect of containing glass fiber on crack fracture durability was also confirmed to be effective.In this case, however, the melt fracture durability was 7 W, and the overall condition including the melt fracture durability and the crack fracture durability was comprehensive. From the viewpoint of durability, it can be seen that the application of aluminum borate whiskers is effective.

As can be seen from the above results, the resin compound as the sealing material for the high heat generating element can improve the heat conductivity and prevent the melt fracture and the crack fracture by containing the reinforcing material. By compounding PPS and aluminum borate whisker in an appropriate amount, a high thermal conductor of aluminum borate, a sealing material for electronic components that is rich in durability against melt fracture and crack fracture due to strengthening action, and can do.

(Effects of the Invention) According to the present invention, it is possible to obtain a resin composition having good thermal conductivity and excellent mechanical strength with very few occurrences of cracks and the like. As a result, even when encapsulating a high heating element such as a resistor, it has a simple structure without providing a heat sink, etc., does not cause melting or cracking during circuit operation, and can withstand stable use for a long time. Can be manufactured. Therefore, the circuit can be reduced in size and weight, and since the sealing material is a resin composition that can be compounded, sealing can be easily performed by injection molding or the like, and the productivity is high and the cost merit is great.

[Brief description of the drawings]

FIG. 1 is a perspective view of a resistor sealed with the sealing resin composition of the present invention, and FIG. 2 is a sectional view thereof. 1: Sealed body 2: Resistor 3: Resistor lead wire

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 23/31

Claims (1)

(57) [Claims] 1. A sealing resin composition comprising a polyphenylene sulfide resin and fibrous and / or whisker-like aluminum borate.